The aim of the project is to understand the enzymatic and genetic basis for the unusual nutritional versatility of the opportunistic pathogen Pseudomonas cepacia. Our original premise was that the extreme biochemical diversity of P. cepacia might be related to the evolution of multifunctional enzymes that would afford greater enzymatic capabilities without a corresponding increase in genome size. Our studies of glucose degradation and of branched chain- and hydroxy- amino acid degradation indicate that this is not the case. The unusual nutritional diversity of P. cepacia seems to correlate with a greater complexity of its complement of pathway enzymes. Current directions of our work are: (1) To examine the contribution of high molecular weight plasmids we have detected in P. cepacia to its nutritional capacity (2) To explore the possibility that the common loss of pentose shunt isoenzymes we have observed in mutant strains of P. cepacia might be related to the loss of a plasmid. (3) To define the association of the chloroform sensitive phage, CP1, with P. cepacia (CP1 DNA appears to be integrated into the chromosome of its P. cepacia host or carried as a plasmid depending upon the host strain). Another direction of the work is to examine the role of the poorly understood direct oxidative route of glucose degradation. Mutant studies indicate that in P. cepacia this route is not essential for growth on glucose. Pathway enzymes are membrane associated, but are readily solubilized by detergents without loss of activity. Further characterization of the enzymes should contribue to a better understanding of the direct oxidative pathway.